The embodiments described herein relate generally to a yaw assembly for use in wind turbines.
Because many known wind turbines provide electrical power to utility grids, at least some wind turbines have larger components (e.g., rotors in excess of thirty-meters in diameter) that facilitate supplying greater quantities of electrical power. However, the larger components are often subjected to increased loads (e.g., asymmetric loads) that result from wind shears, yaw misalignment, and/or turbulence. The increased loads have been known to contribute to significant fatigue cycles on the components of the wind turbine.
At least some known wind turbines include a nacelle fixed atop a tower. The nacelle includes a rotor assembly coupled to a generator through a shaft. In known rotor assemblies, a plurality of rotor blades extend from a rotor. The rotor blades are oriented such that wind passing over the rotor blades turns the rotor and rotates the shaft, thereby driving the generator to generate electricity. At least some known nacelles include a yaw system for controlling a perspective of the rotor relative to a direction of wind. Known yaw systems are configured to rotate the nacelle about a yaw axis to adjust the perspective of the rotor. Additionally, known yaw systems are configured to maintain a perspective of the rotor with respect to the wind direction. During operation, known wind turbines may be subjected to high velocity wind events that impart an increased rotational moment to the nacelle with respect to a normal wind turbine operation. Known yaw systems are sized to facilitate preventing a rotation of the nacelle during these high velocity wind events. As such, known yaw systems are oversized for normal wind turbine operation.